In the continuing search for improved fuel efficiency, vehicle manufacturers are cutting weight wherever possible. One popular source of weight reduction is that round black thing mounted on a heavy steel wheel lying at the bottom of your trunk – the spare tire. In many cases it is seldom if ever used, and the argument goes that Joe or Jane Consumer will never notice it is missing.
In its place many vehicles are equipped with run-flats, tires especially developed to operate without air inside for short distances at reduced speeds. Generally speaking, these tires have stiff sidewalls designed to carry the weight of the vehicle if the tire is punctured or damaged to the point where it loses air. Acura, Audi, BMW, Cadillac, Chevrolet, Fiat, Honda, Mercedes-Benz, MINI, Nissan and Toyota all have at least one model equipped with run-flat tires.
All is not sweetness and light, however. A recent survey by J D Power and Associates found that consumers are not happy with run-flat tires. The report said folks were unhappy with "premature or uneven wear in certain applications, a stiff ride, high replacement costs, and limited replacement choices."
Canadians have added issues with the need to switch to winter tires. Since tire companies do not make run-flat winter tires these folks have to buy and carry a fifth wheel with no place to put it, or know that if they have a flat, they will be stuck until assistance can be arranged.
The plus side of the equation is that, in addition to the weight savings, run-flats allow more space in the trunk or cargo and remove any concern about having to cope with a flat tire. For many consumers, the prospect of having to change a tire on the roadside ranks right up there with dental surgery on the scale of favorite things to do. Many of these consumers would willingly sacrifice some ride quality — if indeed they noticed the difference — or put up with some other perceived shortcoming in return for the peace of mind of knowing they could get to a service facility if a tire went flat.
Bridgestone has just released a new line of run-flat tires designed for these very consumers, the first full line of mass-market replacement tires developed for coupes, sedans and wagons that were not originally equipped with run-flat tires.
Bridgestone says the new DriveGuard line of tires is "aimed at alleviating the worry, frustration and inconvenience associated with a flat tire."
They give the owner the ability to continue driving up to 80 km at speeds up to 80 km/h "if a puncture or loss of pressure should occur."
Bridgestone cites its own survey, conducted last month by Harris Poll on its behalf, which showed almost 75% of drivers have experienced a flat tire. The survey showed that 60% of these drivers "claim they know how to change a flat tire," but 64% would still call for help, 86% of women and 41% of males.
The new DriveGuard tires employ much of the technology used in the latest generation of original equipment run-flats. "Unlike some earlier generations of run-flat tires, DriveGuard tires deliver the quiet, comfortable ride and confident handling of a premium touring tire," the company says.
DriveGuard tires are available in the United States and Canada for coupes, sedans and wagons with tire pressure monitoring systems (TPMS), and come with an 80,000 - 100,000 km treadwear warranty. They are available in 32 sizes.